| 摘要 |
PROBLEM TO BE SOLVED: To reduce a track count miss at an information access time and to make possible high speed access by providing a tracking continuous groove in addition to a recording layer of a multilayer film disk. SOLUTION: Since a track is an information surface 11A formed by intermittent pit line, a laser light spot passes through a non-pit part at a high speed seek time, and an excellent tracking signal hardly be obtained. For controlling seek operation speed and position of an optical head, a track count signal counting transverse tracks is required, and the precision of the signal decides seek control precision. Although the count precision of the information surface 11A of only the track formed by a phase pit line isn't excellent, the tracking signal isn't deteriorated even when an optical head moving speed is large by providing a track count surface 12A formed on a second layer and constituted of the continuous groove. Thus, the optical head is seek controlled precisely. |
